Pawl-and-ratchet mechanism



(Normaal.)

' A. BREWER.v

Paw] and Ratchet Mechanism.

No. 239,928. Y P'at'en'ted April l2,.fl88l.

I "VI- E .dal

UNITED STATES PATENT EEICE.

ALANSON T. BREWER, OF WATERTOWN, MASSACHUSETTS.

PAwL-AND-RATCHET MECHANISM.

SPECIFICATION forming part of Letters Patent No. 239,928, dated April12, 1881.

Application led March 2, 1881. (No model.)

To ctt whom it may concern:

Be it known that I, ALANsoN T. BREWER, of Watertown, in the county ofMiddlesex and State of Massachusetts, have invented an ImprovedPawl-and-Ratchet Mechanism, of which the following is a full, clear,concise, and exact description, reference being had to the accompanyingdrawings, making a part hereof, in which Figure l is a perspective viewof such parts of a mechanism as are necessary to illustrate myinvention. Fig. 2 is a side elevation.

The object of my invention is to insure the prompt motion ofthe pawltoward the ratchet on thefeedlng-stroke ofthe pawl,and its prompt motionawayfrom the ratchet on the backstroke of the pawl; and my inventionconsists in the combination, with the pawl, of a friction devicearranged to insure the motion of the pawl in its carrier as soon as thecarrier is moved.

In the drawings, the ratchet A is shown on the side of the rim of wheelB, and the pawlcarrier Fis journaled on arbor D, around which wheel Brevolves. In the machine of which Fig. 1 is a part the arbor D is madefast at V each end, and the power applied to the pawlcarrier F istransmitted by wheel B to a pinion (not shown) which meshes with wheelB. The pawl G is journaled at g to the pawl-carrier F, and i's connectedat g" to the friction device H. j

The friction device shown is a friction-strap around arbor D, with alinger projecting from it and passing through pawl G at g. This is thesimplest and most efcient friction device for this purpose known to me.

.The operation is as follows: When the pawl G is out of contact with theratchet A motion of the pawl-carrier F upward (the device being in theposition shown in the drawings) will carry pawl G against the finger offrictionl device H, and this friction device cannot move until forced tomove by the stress of pawl G G, friction device H, and ratchet A withit. On the back slider of pawl-carrier F the first back motion of thatcarrier moves pawl G on its journalg until the outer face of pawl Gbrings up against the pawlcarrier F, orastop carried by it, and thecontinued back motion of the pawl-carrier carries with it pawl G andfriction device H, pawl G being held away from ratchet A.

l have shown in the drawings two pawls G, and two ratchets A; `but adescription of one fully describes both.

A minor feature of my invention consists in clamping'the rim of wheel Bbetween pawl Gu and a'shoulder, J, on the pawl-carrier duringIthe'feeding stroke of the pawl. This is very desirable where any greatpower is to be trans` mitted by the mechanism.

It will be seen that when the pawl takes intov the ratchet it tends tothrow the rim of wheel B away from it, and if a single pawl were usedthe rim of wheel B would be moved in pracf tice some considerablefraction of an inch; but when the shoulder J--say on the right of wheelB in Fig. l-is properly adjusted opposite the engaging-pawl-say the pawlG on the left of wheel B in Fig. l-Ihen any motion of wheel B understress of pawl G (on the left in. Fig. l) .will clamp wheel B firmlybetween pawl G on the left of Fig. 1 and shoulder J on the right of Fig.1, and so of the other pawl` with a shoulder, J, pawl G, and ratchet A,the l Witnesses:

J. E. MAYNADIER, JOHN R. SNOW.

ICO

